Static Arp not sticking for more than 24hrs

Discussion in 'Tomato Firmware' started by Andy Pandy, Oct 2, 2013.

  1. Andy Pandy

    Andy Pandy Reformed Router Member


    I posted earlier in the week about arp and reboot issues I thought I was having but you kind persons resolved them for me. One other thing I have noticed is that when I add a static arp entry via arp -s host mac address and then check via arp -a I see they are there by the PERM status. However the entries have gone some 24hrs later!

    I have also noticed the uptime never seems to show any time longer than my router rebooting every 24hrs without me knowing about it?

    Any ideas guys?


    Last edited: Oct 2, 2013
  2. koitsu

    koitsu Network Guru Member

    The uptime command, or simply looking at the Uptime field in the GUI (under Status / Overview) will tell you how long the kernel (router) has been up (since last losing power or rebooting).

    If you've manually rebooted your router between now and the time you added a static ARP entry, then that would explain why the entry is missing. :) You'll need to manually re-add it every time, which can be done automatically by placing the necessary arp command into the Administration / Scripts / Init GUI section (or possibly Firewall; try either).

    Static ARP entries on Linux do not expire, so either this is a kernel bug or there is something that is manually clearing the ARP table. It may be that a periodic job that runs every 24 hours is doing something with the ARP table. That will require manual reverse engineering on the part of yourself or a developer.

    Also, it is very important you disclose the filename of the firmware you're using. Do not give the version, please just provide the filename.
  3. Andy Pandy

    Andy Pandy Reformed Router Member

  4. Andy Pandy

    Andy Pandy Reformed Router Member

    Hi Koitsu,

    Thank you for your response again. The filename of the firmware Im using is tomato_v128_m79EDFA. I added the static arp entries to firewall scripts and rebooted. The arp entries were still there referenced with the PERM label.


  5. koitsu

    koitsu Network Guru Member

    Hmm, I guess that's the "official" Tomato firmware, not TomatoUSB...

    The lines you added to Firewall will of course take effect on a reboot. You will need to check back in 24 hours to see if the entries are still there. If they're gone, then something is indeed removing them (see my previous post for possibilities).
  6. dc361

    dc361 Network Guru Member

    Actually -- that looks like the 'backup' file name that you would see on Administration->Configuration. I think you could get a more accurate version name from Administration->Upgrade (if you are not running jffs) or even using the ABOUT menu but this still isn't the file name that I believe Koitsu would like to see.
  7. koitsu

    koitsu Network Guru Member

    Ah yeah, that does look like the Configuration Backup filename -- good catch dc361!

    Yeah, I wanted the actual filename of the firmware used. :) The information on the About page is not always sufficient, which is why I always ask for the firmware filename.
  8. Planiwa

    Planiwa Network Guru Member

    I seem to have the opposite problem.

    I set up static IP addresses, but did not check the option "Enable static ARP for all devices on list [ ]".
    Yet I get this:

    root@ROUTER:/tmp/home/root# arp -a
    MYSTERY-APPLE.Domain ( at 00: [ether] PERM on br0
    MYSTERY-SAMSUNG-android-3e............fc.Domain ( at 5C: [ether] PERM on br0
    R.Domain ( at 00: [ether] PERM on br0
    MYSTERY-SAMSUNG.Domain ( at 00: [ether] PERM on br0
    M-iPhone.Domain ( at 60: [ether] PERM on br0
    M.Domain ( at DC: [ether] PERM on br0
    B.Domain ( at 00: [ether] PERM on br0
    Ri.Domain ( at 60: [ether] PERM on br0
    R-i5.Domain ( at D8: [ether] PERM on br0
    root@ROUTER:/tmp/home/root# cat /etc/motd
    Tomato v1.28.9013 MIPSR2-RAF-v1.2i K26 USB
    root@ROUTER:/tmp/home/root# nvram find model_
    t_model_name=Asus RT-N66U
    root@ROUTER:/tmp/home/root# wl assoclist
    assoclist 60:
    assoclist 60:
    assoclist DC:
    Is that how it should be? What am I doing wrong or misunderstanding?

  9. koitsu

    koitsu Network Guru Member

    Planiwa your situation is different/unrelated to this thread. Please make a new one. The two issues are separate/unrelated.
  10. Planiwa

    Planiwa Network Guru Member

    Last edited: Oct 6, 2013
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice